To improve film uniformity during rapid thermal processing (RTP), test substrates referred to as “monitor” substrates may be processed within an RTP tool and then analyzed. For example, stand alone metrology tools such as an ellipsometer or sheet resistance measurement tool may be used to measure film thickness or sheet resistance uniformity. A production process that undergoes similar rapid thermal processing is assumed to have similar film thickness or sheet resistance uniformity. Accordingly, an RTP tool process may be optimized using the information from analyzing monitor substrates, and then the optimized process may used during production.
However, the use of monitor substrates is time consuming and expensive, requiring significant tool time while the monitor substrates are processed and analyzed before the process may be optimized. Accordingly, a need exists for methods and apparatus for determining process uniformity without the use of monitor substrates.